Process Optimization Design Of Liquid Dehydrogenation To Ketones

The dehydrogenation of alcohols to aldehydes/ketones is a relatively mild and safe method,which is suitable for the preparation of some simple structures of aldehydes/ketones.As an example,in the preparation of cyclopentanone,the advantages and disadvantages of the method are displayed by experimental research.And then we put forward the improvement method.For conventional reactive distillation for dehydrogenation of Cyclopentanone,actual reaction selectivity is about 84%.The main by-product is(1,1 ’-bicyclopentyl)-2-one,2-cyclopentylidenecyclopentan-1-one,1 ’-hydroxy-bicyclop entyl-2-one and 1-cyclopentylcyclopentanol.They are aldol condensation and semi ketal reaction products.The experimental results show that the high content of the cyclohexanone in the reaction liquid and the high reaction temperature are the main reasons for the promotion of the side reaction.By using cyclopentone-water or cyclopentanol-water to form the lowest azeotropic property,the reaction temperature is reduced to 110 ℃ by adding third components of water.The reaction distillation method is used to extract the cyclopentanone in time,and the content of cyclopentone in the reaction liquid is reduced to about 10%.After the improvement,the selectivity of the reaction was increased to 97.2%,and the purity of cyclopentone reached more than 99.9%.The by-product hydrogen has been collected,compressed,cooled,dried and purified.Its purity is up to 99.6%.It can be used as a feedstock for hydrogenation.In addition,I also design a complete process flow.It includes reactive distillation,azeotropic dehydration,gas processing,gas-liquid separation and other processes.I use Aspen Plus software for computer simulation.The Peng-Rob\Nrtl physical equation is chosen for the mission.It contains 15 device models,28 streams and 2 loop nesting.Its iterative computation converges successfully and is consistent with the experimental data.After the experimental and computer simulation results are obtained,I do experiments on the pilot equipment.When there is a situation:the reaction temperature is 110 ℃,the catalyst proportion of reaction liquid is 1.5%,cyclopentanol and water feed ratio of 1.36:1,reflux ratio R=5,theoretical plate is 30,dehydration temperature of 134℃,hydrogen compression ratio is 21,compressed cooling to 2 degrees C.Then the purity of cyclopentone is about 99.7%,the purity of hydrogen is about 99.3%,the purity of the recycled water is 99.99%and the comprehensive yield is about 90%.Compared with the original process,the improved process can save 24.68%of the cost of production.